By 1988 more than 100,000 individuals with end-stage renal disease (ESRD) were receiving life sustaining chronic hemodialysis, costing the U.S. Medicare Program over $3 billion annually. Approximately one-half of Medicare's ESRD budget is spent on the procedural costs of delivering dialysis to ESRD patients, the remainder arising from the costs of morbidity and associated hospitalizations Complications of vascular accesses, surgically constructed subcutaneous artificial vascular conduits through which blood is removed for hemodialysis, alone account for one of the most important causes of hospitalization in the ESRD population. In 1986 greater than 14 percent of all ESRD hospitalizations were for the revision of vascular access grafts. The mean time from beginning dialysis to the first access complication was less the 9 1/2 months. Despite this enormous morbidity little is known about potentially modifiable factors which may improve the duration of complication-free survival of hemodialysis access grafts. This project is designed to identify those factors. A prospective cohort study is proposed to identify the surgical, dialysis-related, and medical risk factors associated with early malfunction of synthetic hemodialysis access grafts. Two-hundred and fifty patients from 5 Philadelphia clinical centers receiving a subcutaneously implanted polytetrafluoroethylene (PTFE) arteriovenous bypass graft for hemodialysis access will be recruited over a 3 year period. Baseline medical history, data on surgical technique, data on dialysis, or transplantation. The rate of access failure will be compared among study cohorts exhibiting differing risk profiles. The statistical analysis will be based on a Cox Proportional Hazards Model. Given the number of patients which will be entered into the study, there will be ample power to detect small, clinically important elevations in the rate of access failure for each of the hypothesized risk factors if those elevations truly exist. Thus, this prospective cohort study should be able to identify the important predispositions to shortened complication--free vascular access survival, an extremely important contributor to the morbidity in and costs of caring for the U.S. hemodialysis population.